A predictive thermometer includes a probe tip that is placed in physical contact with a target site, such as a human body site, for the purpose of measuring a temperature of that target site. A temperature of the target site is predicted (estimated) via real time analysis of a temperature rise of the probe tip prior to arriving at thermal equilibrium in relation to the target site. The probe tip may be pre-heated to a pre-determined temperature before temperature estimation. Variations in the manufacture of the predictive thermometer may cause inaccuracies with respect to the estimating the temperature of the target site.